Digital cameras typically include an optical lens and light sensing integrated circuit (IC), such as a complementary metal-oxide semiconductor (CMOS) or charge-coupled device (CCD). Light sensing ICs traditionally have light sensing elements that are aligned with the image captured by the optical lens. In this fashion, the individual light sensing elements can provide a signal representative of the intensity of the light to which a particular area of the image is exposed.
However, under flickering light conditions, such as fluorescent lighting, digital camera image quality can be substantially reduced since the intensity lighting conditions are not constant. For example, known image de-blurring processing requires one to first calculate the point spread function (PSF). When the light intensity is constant over time, the PSF can be computed simply as a function of the camera motion. However, if the light source is flickering (e.g., a fluorescent lamp), the knowledge of the motion alone is insufficient for accurately calculating the PSF, as the PSF is similarly affected by illumination factors, such as the phase and the contrast of the light source.
Since digital cameras are used a large percentage of the time indoors under fluorescent lighting, there is a need in the art for image processing techniques under flickering lighting conditions, such as image de-blurring, exposure timing and/or motion estimation.